Soil and Sediment Assessment Web Application
Rey Farve, Project Leader
For Fiscal Year 2012, Michael Crump, Southern Region (R8) hydrologist, submitted a proposal to the Technology and Development Program's Inventory and Monitoring Steering Committee to investigate and develop a computer tool to assess soil and sediment contamination.
The proposal was a request to develop a computer tool (ideally a Web-based tool) to assist hydrologists and soil scientists with documenting the background levels of inorganic chemicals on national forest lands and help these soil specialists assess whether ground-disturbing activities have contributed to increases in geochemical concentrations.
Certain land use practices may contribute to an increase of metal concentrations in soils. Ground disturbing activities (such as vegetation management and prescribed burns) can mobilize and redistribute metals and other inorganic material in soils. Permitted land uses, such as mineral operations, can produce byproducts and discharges that have a metal residue signature. Nonpermitted land uses, such as chemical spills, illegal dumping, abandoned mine land, also can be a source of inorganic chemical contamination. Increased metal concentrations within the soil can indicate that additional clean up or mitigation is required.
In either permitted or nonpermitted events, land managers need to have a general understanding of the unimpaired, natural (background) conditions at or near a disturbed site so that staff can monitor any reclamation efforts to determine if soil quality and productivity has been returned to pre-activity conditions.
Timber logging operation (permitted)
Illegal dumping (nonpermitted)
Region 8 sediment analysis practices
Region 8 typically uses existing soil geochemical data from the U.S. Geological Survey’s (USGS) National Geochemical Survey (NGS) as its information source for values of soil/sediment background geochemical/elemental concentration (USGS 2004; also see a more detailed discussion on NGS in "Dataset" section). Below is an example of a NGS map; this map shows selenium levels nationwide.
National geochemical map for selenium (from USGS - NGS)
Additionally, Region 8 uses U.S. Environmental Protection Agency’s (EPA) Level III EcoRegion areas to stratify watersheds into areas with similar geology, physiography, soils, vegetation, and hydrology (USEPA 2005). Region 8 considers the Level III EcoRegion as a logical unit for grouping geochemical information and for evaluating soil and sediment samples (Crump 2011). (See more detailed discussion in the "Dataset" section.)
U. S. EPA Level III EcoRegions
Level III EcoRegions in Region 8
Example showing a subset of NGS data sites within a subset of Level III EcoRegions.
Region 8’s process of using NGS data by Level III EcoRegions allows soil and sediment samples to be collected (and analyzed) for a specific area and assists in establishing a standard practice for comparison of background geochemical levels against field-collected geochemical levels.
Many times the biggest challenge for soil monitoring is characterizing initial conditions and developing an understanding of appropriate background geochemical values. This challenge can be overcome by using the NGS as the primary source of information for determining relevant background values (Crump 2011).
Soil monitors in Region 8 (or nationwide) would benefit from automating this process of comparing and reporting/documenting soil/sediment geochemical levels from a target site against existing background levels within the EcoRegion. A computer tool could produce reports that display the comparison in an easy-to-read format that users can print and include in permit administration folders or export as a PDF and attached within databases. The report generated by the computer tool also could list acceptable environmental standards for constituents where they exist.
This tool also could assist users with screening for any potential issues of inorganic contamination. Having an available online database and tool would be very useful for assisting natural resource managers in responding to unplanned emergencies, such as a spill or release of material that could be a source of inorganic element contamination. In many instances, a basic understanding of the background conditions for an area is not readily available for a potential release site prior to it occurring, especially during an emergency when time is of the essence and this information is time consuming to develop. In these situations, users can use this tool as a rapid surrogate to provide quick feedback for initial response.
The objective of this project was to develop a prototype computer tool to assess soil and sediment contamination.
The computer tool would be a Web-based application that would:
- Populate with data derived from the USGS National Geochemical Survey Dataset.
- Retrieve background geochemical levels of a specified areas (EcoRegions),
- Compare these background levels to levels collected in the field in a statistically appropriate manner.
- Retrieve information from other sources relative to acceptable levels of geochemical concentration,
- Produce reports.
The intent is that the computer tool would be usable by soil scientists for Region 8 or nationally throughout the Forest Service.
San Dimas Technology and Development Center, in partnership with Region 8’s hydrologist, contracted with NorthStar Technology Corporation (Marc Todd, computer programmer) for the development of the Web-based computer tool.